Switching between seismic and seismo-acoustic harmonic tremor simulated in the laborator:Insights into the role of open degassing channels and magma viscosity
Switching between seismic and seismo-acoustic harmonic tremor simulated in the laborator:Insights into the role of open degassing channels and magma viscosity
复制标题
实验室模拟的地震和地震声谐波颤动之间的切换：深入了解开放脱气通道和岩浆粘度的作用
DOI：
10.1002/jgrb.50067
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and J. Lees
中科院分区：
文献类型：
--
作者：
J. Lyons;M. Ichihara;A. Kurokawa;and J. Lees
据报道，全球少数火山在纯地震谐波震颤（SHT）和地震声谐波震颤（SAHT）之间切换，但其发生可能表明浅层管道条件发生了重要变化。在实验室实验中模拟了开关，其中通过流量驱动阀和压缩空气产生谐波信号。谐波信号通过剪切稀化粘弹性流体罐，并记录所得信号。在高流体刚度下，产生了稳定的开放导管，并且实验装置内产生的谐波信号被有效地传输到大气中。在较低的流体硬度下，起泡主导了活动，流体中没有产生稳定的路径，并且大气中没有记录到 HT。这些结果与危地马拉富埃戈火山转换的观测结果进行了比较。我们得出的结论是，在中等岩浆粘度下，向大气开放的稳定脱气通道的发展将使管道中产生的HT能够传输到大气中。此外，岩浆性质和供应速率的细微变化可能会控制是否记录 SHT 或 SAHT，从而提供有关活火山浅层管道和喷口状态的信息。
Switching between seismic‐only harmonic tremor (SHT) and seismo‐acoustic harmonic tremor (SAHT) has been reported at few volcanoes worldwide, but its occurrence may indicate important changes in shallow conduit conditions. Switching was simulated in a laboratory experiment in which harmonic signals were produced with a flow‐driven valve and compressed air. The harmonic signals were passed through a tank of shear‐thinning viscoelastic fluid, and the resulting signals were recorded. At high fluid stiffness, a stable, open conduit was produced, and the harmonic signals generated within the experimental apparatus were efficiently transmitted into the atmosphere. At lower fluid stiffness, bubbling dominated the activity, stable pathways were not generated in the fluid, and HT was not recorded in the atmosphere. These results are compared to observations of switching at Fuego volcano, Guatemala. We conclude that at intermediate magma viscosities, the development of stable degassing pathways open to the atmosphere will allow HT generated in the conduit to be transmitted into the atmosphere. Further, subtle changes in magma properties and supply rate may control whether SHT or SAHT is recorded, providing information about the state of the shallow conduit and vent at active volcanoes.